Previous Year Questions (PYQ) | 2025-March_Evening_Shift | CSIR-NET Life Sciences

QUESTION ID:1

An ecologist calculates the Shannon-Wiener diversity index for an ecosystem with high species diversity. Which one of the following statements about this diversity index is INCORRECT?

It increases as species richness increases.

It is maximized when all species have equal abundances.

It is unaffected by the evenness of species abundances.

A low index value indicates dominance of one or a few species.

https://triyambak.org/courses/csir-net-life-sciences/tpp/pyq?qid=32204&year=2025&month=March_Evening_Shift

QUESTION ID:2

Presence of E-cadherin activates the Hippo pathway in the inner cell mass (ICM). Experimentally eliminating E-cadherin disrupts both apicobasal polarity and specification of the ICM and trophoectoderm lineages. Which one of the following schemes leads to pluripotency?

https://triyambak.org/courses/csir-net-life-sciences/tpp/pyq?qid=32205&year=2025&month=March_Evening_Shift

QUESTION ID:3

With reference to the origin of multicellularity in different life forms, which one of the following statements is INCORRECT?

The 'snowflake yeast' experiment demonstrated the evolution of multicellularity through cell adhesion and programmed cell death.

The syncytial theory states that multicellular organisms arose through the aggregation of free-living unicellular forms.

Cadherin-based adhesion pathways played an important role in the evolution of multicellularity in plants.

Co-option of existing functions is hypothesized to have driven the evolutionary transition from undifferentiated multicellular clusters to differentiated tissues.

https://triyambak.org/courses/csir-net-life-sciences/tpp/pyq?qid=32206&year=2025&month=March_Evening_Shift

QUESTION ID:4

A researcher studying the mating systems in birds (operational sex ratio 1:1) uses the number of successful matings as a measure of male reproductive fitness and female reproductive fitness, as depicted in the figure below.

Which one of the following options correctly matches P and Q with the correct sex for different mating systems?

Polygyny: P, male, Q, female; Polyandry: Q, male, P, female

Polygyny: Q, male, P, female; Polyandry: P, male, Q, female

Polygyny: P, male, Q, female; Polyandry: P, male, P, female

Polygyny: Q, male, P, female; Polyandry: Q, male, Q, female

https://triyambak.org/courses/csir-net-life-sciences/tpp/pyq?qid=32207&year=2025&month=March_Evening_Shift

QUESTION ID:5

The mechanisms of action of calcitropic hormones are important for understanding the molecular basis of disease states related to calcium homeostasis.

A. Calcium binding (transport) protein (CaBP) enhances the movement of calcium from the brush border into the cytoplasm.

B. Receptors for calcitonin are present in the osteoclasts where they increase CAMP production.

C. Parathormone essentially works independently to mobilize bone mineral, and never in concert with vitamin D.

D. The major calcitropic hormone, calcitriol, regulates intestinal calcium absorption.

Which one of the following options is INCORRECT in maintaining calcium homeostasis?

A and B

Only B

Only C

C and D

https://triyambak.org/courses/csir-net-life-sciences/tpp/pyq?qid=32208&year=2025&month=March_Evening_Shift